This "face" is just a natural landform. These things happen a lot, you can get a lot of diffrent shapes and sizes from natural landform this one on mars just happens to look like a really realistic face. Plus the "face" has changed alot from 1976 to 2001 and we saw the face change with no alien near by changing it and not cause of the camera but because this natural landform is getting older and soon you won't ever be able to tell it was there. There will be other natural landforms and might look like a face. The spacecraft circling the planet would've caught an alien near by . Also it looked alot more like a face in 1976 because the landform is changing and moving so the "face" moves and changes with it. Then the team went out there to snap photos and all they got was a sharper view of the "face", and no one near by except them. There could be a lot of landform shapes, one could look like a animal or something. These landforms can look like a lot of things and be natural landform and can be creating without aliens. So far we haven't had any proof of aliens ethier. I believe if aliens were real we would find some by now cause we have spacecrafts around certain planets and we've been to the moon and still nothing. Maybe in the future we could find aliens but not now and it's been a while since the "face" has been created and we have no proof of aliens and we didn't back then ethier.